How to Count Words with Repeated Letters in a String Using Python

Discover how to write a Python program that counts specific words in a string with letters that repeat a certain number of times. Learn with examples and code solutions.
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How to Count Words with Repeated Letters in a String Using Python

Python is a powerful programming language that allows us to manipulate strings and analyze data effortlessly. One common challenge that developers face is counting specific words in a string based on certain criteria—in this case, counting words that contain letters that repeat a specified number of times successively. In this blog, we will walk through the solution to this problem step-by-step.

Understanding the Problem

The task is to write a Python program that returns the number of words in a given string where specific letters repeat a defined number of times. For example, if we specify that the letter should repeat twice, and we have the string "first loop ddd", the program should return 1, because only the letter 'o' in the word "loop" repeats twice. The letter 'd' in "ddd" does not count since it repeats three times.

Solution Overview

We can break down the solution into the following steps:

Split the String into Words: Use whitespace to break the input string into individual words.

Check Each Word for Repeated Letters: Analyze each word to determine if any letter repeats the specified number of times.

Store Unique Words: Use a set to ensure that we only count unique words, which reduces duplication in our results.

Return the Count: Finally, return the count of unique words that satisfy the criteria.

Let’s look at how to implement this in Python.

Step-by-Step Code Explanation

Initial Approach

Firstly, we will write a basic version of our function that checks for repeated letters without using regular expressions. Here’s a straightforward code implementation:

[[See Video to Reveal this Text or Code Snippet]]

Code Explanation

Function Definition: We define a function called find_repeats that takes a string and a number r.

Lowercase Conversion & Splitting: We convert the entire string to lowercase and split it into individual words.

Filter for Alphabetical Characters: We remove any non-alphabetic characters from each word.

Count Repeated Letters: For each letter in the word, we check if it repeats exactly r times and does not repeat more (check for r + 1).

Count Unique Words: The found words are stored in a set to ensure uniqueness.

Enhanced Approach with Regular Expressions

To handle complex cases, let's enhance our implementation using Python's regular expressions:

[[See Video to Reveal this Text or Code Snippet]]

Enhanced Code Explanation

Greedy Matching: The regex letter + matches one or more occurrences of the letter in a word, enabling us to grab consecutive repetitions effectively.

Conclusion

Now you know how to count words in a string that contain specific repeated letters using Python! This solution not only enhances your coding skills but also prepares you for similar tasks you might encounter in data processing and string manipulation.

Feel free to experiment with different strings and repetition values to see how this code can be applied in various scenarios!